Do you really want to see what happens when you go from a 20 or 22 megapixel sensor to a 46 megapixel sensor? Do you want to see how the lens affects sensor sharpness? Take your lens, mount it on your FF camera, take a photo that shows off sharpness. Then take that lens, mount it on a Rebel, and do the same. You will find that only lenses of superior sharpness will give you a sharp image on your Rebel...... and that is what will happen when you go full frame high megapixel....

Unless you have a camera bag full of the finest L-glass, you can rant on and on about which sensor and which camera outresolves who..... but out in the real world most people have bought into a SYSTEM.... and by far the most important part and the most expensive part of that system is the glass....

You can take the crappiest Nikon DSLR, put a high end lens on it, and it will outresolve the finest Canon camera with a kit lens. Likewise, take the crappiest Canon, put on some high end L-glass, and it will outresolve the finest Nikon with a kit lens.

You want to know the order of things? #1 - photographer#2 - glass#3 - camera

..... and the glass is an investment while the camera can be best thought of as expendable.

Sorry for the rant, but this thread has degenerated into another DXO/SENSOR/NIKON/CANON arguefest, most of which has nothing to do with the topic at hand..

I think that is why Canon has been doing alot of len upgrades. I think they are making sure that users who will buy a Big MP body will be able to get results out of it via the new L glass. Just MHO, but I think Canon is smart to upgrade glass first.

I think that is why Canon has been doing alot of len upgrades. I think they are making sure that users who will buy a Big MP body will be able to get results out of it via the new L glass. Just MHO, but I think Canon is smart to upgrade glass first.

+1 I have been thinking along the same lines as this, above.

Canon has made some very good moves regarding digital photography in the past (eg first in FFs, first DSLR with video and live-view, etc).

So the idea of first getting a suitable amount of high quality lenses to get the most of any increased MP DSLRs (particularly FF) makes a lot of sense to me.

When I upgraded from an 8MP 350D to a 18MP 7D, the requirement for better glass to get the most out of the increased resolution / sensor was clear to me. I now have high quality lenses covering 10mm to 300mm, including Canon L glass too.

Regards

Paul

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I appreciate using my 7D and 350D cameras along with a host of lenses & many accessories to capture quality photos, and share with friends.

Do you really want to see what happens when you go from a 20 or 22 megapixel sensor to a 46 megapixel sensor? Do you want to see how the lens affects sensor sharpness? Take your lens, mount it on your FF camera, take a photo that shows off sharpness. Then take that lens, mount it on a Rebel, and do the same. You will find that only lenses of superior sharpness will give you a sharp image on your Rebel...... and that is what will happen when you go full frame high megapixel....

Unless you have a camera bag full of the finest L-glass, you can rant on and on about which sensor and which camera outresolves who..... but out in the real world most people have bought into a SYSTEM.... and by far the most important part and the most expensive part of that system is the glass....

You can take the crappiest Nikon DSLR, put a high end lens on it, and it will outresolve the finest Canon camera with a kit lens. Likewise, take the crappiest Canon, put on some high end L-glass, and it will outresolve the finest Nikon with a kit lens.

You want to know the order of things? #1 - photographer#2 - glass#3 - camera

..... and the glass is an investment while the camera can be best thought of as expendable.

Sorry for the rant, but this thread has degenerated into another DXO/SENSOR/NIKON/CANON arguefest, most of which has nothing to do with the topic at hand..

Yep... I don't know why people can't figure this out. This sort of thinking used to be common sense in teh film days.

So, by DxO's criteria and definition, Canon's best prime and zoom lens are basically not limiting system resolution (within a 1 MP margin of error). However, Nikon's best prime and zoom on the D800 are resulting in the 'loss' of 14-15 MP....resulting in a perceived sharpness of even Nikon's best lenses on the D800 as no better than Canon's best lenses.

Interestingly, while the D800 appears to be 'too much' for Nikon lenses in that the lenses are clearly limiting overall system resolution, we don't know from these data if we're at the limit of the Canon lenses.

Yet, 7D shows markedly better resolution than 40D in combination with the same lenses. In fact, with quite a few lenses, not only the very best ones.

So, if these systems benefit from increased pixel density from 25.6 to 46 MP FF sensor equivalent, how can the best lenses be the limiting factor at 21-22 MP? Or am I misunderstanding something?

Pixel density isn't the only factor - sensor size matters.

Can you elaborate, please? I mean, if you were to take a hypothetical 25.6 MP FF sensor and use scissors to trim it by a factor of 1.6 in each dimension, you'd end up with a 10 MP APS-C sensor. Using the same lens, there should be no difference how it resolves before and after trimming, right?

Can you elaborate, please? I mean, if you were to take a hypothetical 25.6 MP FF sensor and use scissors to trim it by a factor of 1.6 in each dimension, you'd end up with a 10 MP APS-C sensor. Using the same lens, there should be no difference how it resolves before and after trimming, right?

P-Mpix isn't a measure of resolution, although resolution is a contributing factor. Resolution ≠ sharpness. A true measure of spatial resolution involves a physical distance. Usual units are line pairs / mm (LP/mm). For a spatially normalized measure in LP/mm, the higher density sensor will outresolve the lower density sensor.

However, that's a per-unit basis - and that's not how we look at images. MTF50, a commonly used measure of sharpness, is reported in line pairs / picture height (LP/PH). In that case, the greater 'height' of a FF sensor means higher values. You can see that on photozone.de - when you compare a lens on FF vs. APS-C, the MTF50 values will be higher for the 5DII tests than the 50D tests, despite the higher pixel density of the 50D. This isn't just a numerical phenomenon - take a look at the TDP comparison of two 18 MP sensors, the 1D X vs. the 7D (same lens, the 200/2L IS at f/4). The 1D X is producing a noticeably sharper image.

That difference you see in TDP's ISO 12233 crops can be measured by SQF, and that's basically what P-Mpix is telling you. For example, the Canon 300mm f/2.8L IS II that delivers 22 P-Mpix on the 5DIII achieves only 14 P-Mpix on the 7D. In fact, the 300mm f/4L IS at $1400 delivers better perceived sharpness on the 5DIII than the $7000 supertele lens on the 7D.

i.e. for her that is the killer feature of the Canon 650 and it is things like this that let Canon get away with not improving IQ.

Canon are adding bells and whistles to their camera rather than improving its abilities to take better photos.

The real answer to that is the so-called "IQ" of the Canon equipment is essentially the same as that of Nikon (Pentax, Sony, Oly..., pick your favorite). The output of the equipment when used properly will be essentially indistinguishable. So she was correct, pick the gear based on price and feature set.

It is anyone’s guess as to why Canon has not bothered to make changes to their implementation but one valid guess is that they see no urgent need to fix something that isn’t really broke. Canon is successful because the equipment does an admirable job of producing stunning images that can hold their own against any of the rest.

............That difference you see in TDP's ISO 12233 crops can be measured by SQF, and that's basically what P-Mpix is telling you. For example, the Canon 300mm f/2.8L IS II that delivers 22 P-Mpix on the 5DIII achieves only 14 P-Mpix on the 7D. .............

And that's why I was pleasantly surprised not to miss the crop factor on switching to 1Dx from 7D. Actually it's what made me trade in the 7D for the 5D3 as back up. (Not that the 7D has suddenly become a poor camera, I still have plenty of shots taken with it that I love)

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If you debate with a fool onlookers can find it VERY difficult to tell the difference.